A new bound on the absorption coefficient of a two-phase medium. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 94, p. 123–131, 2002. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/195. Acesso em: 14 dec. 2025.